Outer sole having resilient mid-sole with floating hinges

ABSTRACT

An outer sole includes an upper sole, a tread layer disposed below the upper sole, and a resilient mid-sol disposed between the upper sole and the tread layer. The mid-sole resists compression under load, and comprises at least one floating hinge extending transversely to the longitudinal axis of the sole. Each floating hinge includes an upper resilient convex leaf spring, a lower resilient convex leaf spring, and a U-spring joining the leaf springs together. Each leaf spring has a root and a head opposite the root. Each U-spring has a pair of integrally-formed legs, each upper leaf spring is integrally formed at the root thereof with the upper sole, and each lower leaf spring is integrally formed at the root thereof with the tread layer. The leaf springs of each floating hinge are integrally joined at their heads to one of the legs of the associated U-spring.

FIELD OF THE INVENTION

The invention relates to a sole having foot cushioning means. Inparticular, the invention relates to an outer sole for a shoe or boot,having a resilient mid-sole for cushioning the foot while walking orrunning.

BACKGROUND OF THE INVENTION

With the increasing popularity of low-impact forms of cardiovascularexercise, several walking and athletic shoe designs have emerged thatare intended to cushion the foot from impact.

For instance, Schwab (U.S. Pat. No. 3,662,478) describes a shoe solehaving a tread profile consisting of a longitudinal rib, and severallateral grooves that branch off from the longitudinal rib. The groovesare inclined at an angle not exceeding 90°, relative to the longitudinalrib. The grooves create several lateral ribs over which the load of thewalker is distributed.

Stubblefield (U.S. Pat. No. 4,372,058) describes a shoe sole havingflexible lugs that extend downwardly from the lower surface of the sole.The lugs are inclined at an obtuse angle relative to the lower surface,and spread outwardly upon impact with the ground.

Cohen (U.S. Pat. No. 4,754,559) describes a shoe having a mid-sole, anouter sole, and plurality of rib-pairs disposed between the mid-sole andthe outer sole. The rib-pairs are provided along the entire length ofthe shoe, each comprising a pair of oppositely-bowed ribs that extendtransversely to the longitudinal axis of the shoe. The ribs areconstructed from a rubber or similar material. The oppositely-bowed ribsof each rib-pair are separated from one another by a distance thatallows the rib-pairs to deform as the load on the shoe increases. Aftera predetermined load is applied, one of the ribs of each rib-pair abutsthe adjacent oppositely-bowed rib, to thereby increase the load requiredfor further deformation of the rib-pairs.

Diaz (U.S. Pat. No. 4,815,221) describes a shoe sole having a springplate and several curved, tubular resilient lugs projecting downwards orupwards from the plate. The resilient lugs, which have a substantiallyU-shaped cross-section, are deformed under the load of the foot, andreturn to their uncompressed state when the foot is lifted. A supportrib positioned at the rear of each lug urges each lug forward as the lugreturns to its uncompressed state.

Sessa (U.S. Pat. No. 5,469,639) describes a shoe outsole having a recessformed in its upper surface, and a resilient midsole insert positionedwithin the recess. The insert has several longitudinally-spaced,downwardly extending transverse ribs that extend across the lowersurface of the insert. The transverse ribs are of two lengths, with thelonger ribs alternating with the shorter ribs in a regular pattern alongthe length of the insert. The ribs are disposed in a sinusoidal patternacross the width of the insert, with the height of each rib varying in asinusoidal pattern across the width of the insert. The taller ribsprovide a first cushioning rate, while the short ribs provide agradually-increasing cushioning rate upon further compression of theribs.

Parisotto (GB 2 297 768) describes a shoe outersole having a cavitydisposed in the upper surface of the outersole, at the heel portionthereof, and a central longitudinal rib and several transverse ribsdisposed within the cavity. The transverse ribs intersect thelongitudinal rib, to thereby form a grid pattern. The transverse ribsextend upwards from the upper surface of the cavity, and are inclinedrearwardly towards the rear of the shoe. In use, the transverse ribsflex rearwardly under the weight of the heel of the foot, and return totheir undeformed position when the foot is lifted.

Lekhtman (WO 2005/025381) describes a cushioning outsole comprising anupper load bearing member, a lower load bearing member, a plurality ofcompressible spring members disposed between the load bearing members.Each compressible spring member has a bi-concave V-shape, and comprisesa pair of arcuate panels that are contiguous with one another at oneend, and are pivotally coupled to a respective load bearing member viabearing means provided at their respective opposite ends.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided an outersole comprising an upper sole, a tread layer disposed below the uppersole, and a resilient mid-sole disposed between the upper sole and thetread layer and being configured to resist compression under load. Themid-sole comprises at least one floating hinge extending transversely tothe longitudinal axis of the sole. Each floating hinge includes an upperresilient convex leaf spring, a lower resilient convex leaf spring, anda U-spring joining the leaf springs together. Each leaf spring has aroot and a head opposite the root. Each U-spring has a pair ofintegrally-formed legs, each upper leaf spring is integrally formed atthe root thereof with the upper sole, and each lower leaf spring isintegrally formed at the root thereof with the tread layer. The leafsprings of each floating hinge are integrally joined at their respectiveheads to a respective one of the legs of the associated U-spring.

According to another aspect of the invention, there is provided a footcovering comprising a shoe upper, and an outer sole secured to the soleupper. The outer sole comprises an upper sole, a tread layer disposedbelow the upper sole, and a resilient mid-sole disposed between theupper sole and the tread layer and being configured to resistcompression under load. The mid-sole comprises at least one floatinghinge extending transversely to the longitudinal axis of the sole. Eachfloating hinge includes an upper resilient convex leaf spring, a lowerresilient convex leaf spring, and a U-spring joining the leaf springstogether. Each leaf spring has a root and a head opposite the root. EachU-spring has a pair of integrally-formed legs, each upper leaf spring isintegrally formed at the root thereof with the upper sole, and eachlower leaf spring is integrally formed at the root thereof with thetread layer. The leaf springs of each floating hinge are integrallyjoined at their respective heads to a respective one of the legs of theassociated U-spring.

According to another aspect of the invention, the leaf springs areconfigured to resist the compression by progressively straighteningunder the load.

According to another aspect of the invention, the U-springs areconfigured to resist the compression by progressively compressing underthe load.

According to another aspect of the invention, the U-springs are disposedequidistantly between the upper sole and the tread layer.

According to another aspect of the invention, the upper sole includes atoe region and a heel region, and each floating hinge has the U-springoriented towards the toe region.

According to another aspect of the invention, the mid-sole includes anintervening channel disposed between each adjacent pair of the floatinghinges, and the floating hinges and the intervening channels extendcontinuously, without interruption, across the width of the sole.

According to another aspect of the invention, the leaf springs extendtransversely across the entire width of the sole.

According to another aspect of the invention, the thickness of each leafspring is substantially constant between the root and the head thereof.

According to another aspect of the invention, the thickness of each leafspring is substantially constant across the entire width of the sole.

According to another aspect of the invention, the height of the floatinghinges is greater proximate the heel region than the toe region.

In one implementation, the mid-sole comprises a resilient rubbermaterial.

In another implementation, the shoe upper and the outer sole of the footcovering together comprise a shoe.

In another implementation, the shoe upper and the outer sole of the footcovering together comprise a boot.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings, in which:

FIG. 1 is a side elevation of a shoe having an outer sole, showing theupper sole, the tread layer and the resilient mid-sole;

FIG. 2 is a side elevation of the shoe depicted in FIG. 1, showing themid-sole compressed under load;

FIG. 3 is a longitudinal cross-sectional view of the outer sole depictedin FIG. 1, showing the mid-sole in its undeformed state;

FIG. 4 is a longitudinal cross-sectional view of the outer sole, showingthe mid-sole compressed under load;

FIG. 5 is a magnified cross-sectional view of the toe region of theouter sole;

FIG. 6 is a magnified cross-sectional view of the heel region of theouter sole;

FIG. 7 is a perspective view of the outer sole;

FIG. 8 is a side elevation of the outer sole; and

FIG. 9 is a rear elevation depicting the heel region of the outer sole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning to FIG. 1, an athletic or walking shoe 100 is shown comprising aconventional shoe upper 102, and an outer sole 200 secured to the shoeupper 102. The outer sole 200 is secured to the shoe upper 102 in aconventional manner, such as with shoe cement.

As shown in FIG. 3, the outer sole 200 includes a upper sole 202, atread layer 204 disposed below the upper sole 202, and a resilientmid-sole 206 disposed between the upper sole 202 and the tread layer204. Preferably, the upper sole 202, the read layer 204, and themid-sole 206 are fabricated from a resilient rubber compound. Further,preferably the mid-sole 206 is integrally molded with the upper sole 202and the tread layer 204.

The upper sole 202 has a toe region 208 proximate one end of the uppersole 202, and a heel region 210 proximate the opposite end of the uppersole 202. In use, when a human foot is inserted into the shoe 100,between the shoe upper 102 and the outer sole 200, the toes of the footwill reside proximate the toe region 208, and the heel of the foot willreside proximate the heel region 210.

Preferably, the upper sole 202 is integrally molded with the tread layer204 proximate the toe region 208, but is only coupled to the tread layer204 at the heel region 210 via the mid-sole 206 and a flexible U-shapedhinge 226 that protrudes rearwardly from the outer sole 200. As willbecome apparent, this arrangement allows the upper sole 202 to movevertically relative to the tread layer 204, at the heel region 210, whenthe outer sole 200 is under load to thereby provide vertical cushioningto the foot.

Preferably, the tread layer 204 includes several substantially parallelresilient ribs 212 that serve to increase the traction of the shoe 100.Each rib 212 extends downwardly away from the upper sole 202,transversely across the width of the tread layer 204.

The resilient mid-sole 206 includes at least one floating hinge 214 thatis oriented transversely to the longitudinal axis of the outer sole 200.Preferably, the resilient mid-sole 206 includes several such floatinghinges 214 disposed along the entire length of the outer sole 200. Aswill be come apparent, the floating hinges 214 configure the mid-sole206 to resist compression when the outer sole 200 is under load.

As shown, each floating hinge 214 comprises an upper resilient leafspring 216, a lower resilient leaf spring 218, and a U-spring 220 thatjoins the leaf springs 216, 218 together. The upper leaf spring 216 hasa root portion 216 a, and a head portion 216 b opposite the root portion216 a. Each upper leaf spring 216 is integrally formed with the uppersole 202 at the root portion 216 a. Similarly, the lower leaf spring 218has a root portion 218 a, and a head portion 218 b opposite the rootportion 218 a. Each lower leaf spring 218 is integrally formed with thetread layer 204 at the root portion 218 a.

As shown, the leaf springs 216, 218 each have a convex profile, with theradius of curvature of each leaf spring 216, 218 being greater proximatethe root portion 216 a, 218 a than the head portion 216 b, 218 b.However, the profile of each upper leaf spring 216 is opposite to theprofile of each lower leaf spring 218.

The leaf springs 216, 218 extend transversely across the outer sole 200,preferably across the entire width of the outer sole 200. Preferably,the thickness of each leaf spring 216, 218 is substantially constantbetween the root portion 216 a, 218 a and the head portion 216 b, 218 b,and is substantially constant across the entire width of the outer sole200.

In addition, preferably the mid-sole 206 includes an intervening channel222 disposed between each adjacent pair of the floating hinges 214, suchthat the floating hinges 214 and the intervening channels 222 extendcontinuously, without interruption, across the width of the outer sole200. Alternately, one or more of the intervening channels 222 may befilled with a resilient foam material to impart a desired resiliency tothe outer sole 200.

Each U-spring 220 has a pair of integrally-connected legs 220 a, 220 b.One of the legs 220 a of each U-spring 220 is disposed above the otherleg 220 b of the same U-spring 220. Further, each leg 220 a, 220 b issubstantially planar in cross-section, and extends transversely acrossthe width of the outer sole 200. As shown, each U-spring 220 includes achannel 224, defined by the upper leg 220 a and the lower leg 220 b,that extends transversely across the width of the outer sole 200, andseparates the upper leg 220 a from the lower leg 220 b when the outersole 200 is not under load.

The upper leaf spring 216 of each floating hinge 214 is integrallyformed with the upper leg 220 a of the associated U-spring 220 at thehead portion 216 b. Similarly, the lower leaf spring 218 of eachfloating hinge 214 is integrally formed with the lower leg 220 b of theassociated U-spring 220 at the head portion 218 b.

Preferably, the leaf springs 216, 218 have substantially the same lengthand curvature, and the U-springs 220 are disposed equidistantly betweenthe upper sole 202 and the tread layer 204. Further, preferably thefloating hinges 214 are oriented such that the U-springs 220 areoriented towards the toe region 208; and the root portions 216 a, 218 aof the leaf springs 216, 218 are oriented towards the heel region 210.

As discussed above, the leaf springs 216, 218 are resilient in nature,and have opposing convex profiles. Therefore, as the vertical load onthe outer sole 200 increases (eg. due to wearer of the shoe 100 taking astep), the leaf springs 216, 218 will resist vertical compression of theouter sole 200 by progressively straightening under the load.

Due to the varying radius of curvature of the leaf springs 216, 218 (asdiscussed above), the head portions 216 a, 218 a of the leaf springs216, 218 will deflect from their unloaded shape more readily undervertical load (eg. under the weight of the wearer of the shoe 100) thanthe root portions 216 b, 218 b. As the vertical load on the outer sole200 increases, the head portions 216 a, 218 a of the leaf springs 216,218 will abut each other (as shown in FIGS. 2 and 4), thereby preventingfurther deformation of the leaf springs 216, 218 at the head portions216 a, 218 a. However, the root portions 216 b, 218 b of the leafsprings 216, 218 will then begin to deflect from their unloaded shape.As a result, the leaf springs 216, 218 provide progressive verticalcushioning to the foot.

Preferably, each U-spring 220 is resilient, but is more resilient thanthe leaf springs 216, 218. Therefore, upon initial application of thevertical load, the U-springs 220 will resist compression of the outersole 20 first, followed subsequently by deformation of the leaf springs216, 218. As a result, with this latter configuration, more progressivevertical cushioning can be provided to the foot.

Also, preferably the height of the floating hinges 214 is greaterproximate the heel 210 region than the toe region 208 to provideincreased cushioning to the heel of the foot. However, the outer sole200 may have an alternate cross-sectional profile, for enhanced loaddistribution. For instance, the height of the floating hinges 214 may begreater adjacent the areas of the sole 200 that coincide with themaximum load points of the foot, such as the ball and heel of the foot,to provide enhanced support for these regions of the foot.

Numerous variations on the foregoing embodiment are contemplated herein.For instance, typically the mid-sole 206 is modular, in the sense thatthe thickness and size of all the leaf springs 216, 218 aresubstantially the same. As a result, a desired amount of verticalcushioning can be obtained by increasing or decreasing the thicknessand/or size of all the leaf springs 216, 218. Alternately, however, thethickness and/or size of individual leaf springs 216, 218 can beincreased or decreased to provide selective vertical cushioning atspecified locations along the outer sole 200. Further, the amount ofvertical cushioning can be adjusted by the appropriate selection of thematerial from which the leaf springs 216, 218 are constructed.

Also, the number of floating hinges 214 per unit length (density) of themid-sole 206 may be selected to provide a different amount of cushioningto the foot. This density variation may be implemented by eitherincreasing or reducing the size of the intervening channels 222 and/orby increasing or reducing the length and/or angle of incline of the leafsprings 216, 218. Further, the density (as defined above) of thefloating hinges 214 need not be uniform, but instead may vary along thelength of the sole 200. For instance, the density of the floating hinges214 may be greater adjacent the areas of the sole 200 that coincide withthe ball and heel of the foot, and may be lower adjacent the areas ofthe sole 200 that coincide with the arch of the foot.

Further, as discussed above, typically the thickness of each leaf spring216, 218 is substantially constant between the root portion 216 a, 218 aand the head portion 216 b, 218 b, and is substantially constant acrossthe entire width of the outer sole 200. Alternately, however, thethickness of each leaf spring 216, 218 may vary between the root portion216 a, 218 a and the head portion 216 b, 218 b to provide a differentprogressive vertical cushioning profile.

The foregoing description is illustrative of the preferred embodiment ofthe invention, with the claims appended hereto defining the intendedscope of the monopoly for the invention. Those of ordinary skill willenvisage certain modifications to the described embodiment which,although not explicitly suggested therein, do not depart from the scopeof the invention, as defined by the appended claims.

1. An outer sole comprising: an upper sole; a tread layer disposed belowthe upper sole; and a resilient mid-sole disposed between the upper soleand the tread layer and being configured to resist compression underload, the mid-sole comprising at least one floating hinge extendingtransversely to a longitudinal axis of the sole, each said floatinghinge including an upper resilient convex leaf spring, a lower resilientconvex leaf spring, and a U-spring joining the leaf springs together,each said leaf spring having a root and a head opposite the root, eachsaid U-spring having a pair of integrally-formed legs, each said upperleaf spring being integrally formed at the root thereof with the uppersole, each said lower leaf spring being integrally formed at the rootthereof with the tread layer, the leaf springs of each said floatinghinge being integrally joined at their respective heads to a respectiveone of the legs of the associated U-spring.
 2. The outer sole accordingto claim 1, wherein the leaf springs are configured to resist thecompression by progressively straightening under the load.
 3. The outersole according to claim 2, wherein the U-springs are configured toresist the compression by progressively compressing under the load. 4.The outer sole according to claim 3, wherein the U-springs are disposedequidistantly between the upper sole and the tread layer.
 5. The outersole according to claim 4, wherein the upper sole includes a toe regionand a heel region, and each said floating hinge has the U-springoriented towards the toe region.
 6. The outer sole according to claim 5,wherein the mid-sole includes an intervening channel disposed betweeneach adjacent pair of the floating hinges, the floating hinges and theintervening channels each extending continuously, without interruption,across a width of the sole.
 7. The outer sole according to claim 6,wherein the mid-sole includes a resilient foam disposed within thechannels.
 8. The outer sole according to claim 7, wherein the leafsprings extend transversely across the entire width of the sole.
 9. Theouter sole according to claim 8, wherein a thickness of each said leafspring is substantially constant between the root and the head thereof.10. The outer sole according to claim 8, wherein a thickness of eachsaid leaf spring varies between the root and the head thereof.
 11. Theouter sole according to claim 9, wherein the thickness of each said leafspring is substantially constant across the entire width of the sole.12. The outer sole according to claim 11, wherein the height of thefloating hinges is greater proximate the heel region than the toeregion.
 13. The outer sole according to claim 12, wherein the mid-solecomprises a resilient rubber material.
 14. A foot covering comprising: ashoe upper; and an outer sole secured to the shoe, upper, the outer solebeing configured according to any one of claims 1 to
 13. 15. The footcovering according to claim 14, wherein the shoe upper and the outersole together comprise a shoe.
 16. The foot covering according to claim15, wherein the shoe upper and the outer sole together comprise a boot.